(1) Field of the Invention
This invention relates to a novel imidazole-isocyanuric acid adduct (intermolecular compound) and a process for synthesis thereof. More particularly, the invention relates to an imidazole-isocyanuric acid adduct especially valuable as a curing agent or curing promotor for epoxy resins. Further, the invention relates to an epoxy resin composition comprising a novel imidazole-isocyanuric acid adduct, and also to a process for purification of imidazoles utilizing formation of an imidazole-isocyanuric acid adduct.
(2) Description of the Prior Art
Isocyanuric acid is an industrial chemical which is prepared in large quantities from urea. It is known that this isocyanuric acid provides various salts by reaction with inorganic cations (see, for example, Edwin M. Smolin and Lorence Rapoport, S-Triazines and Derivatives, Interscience Publisher Inc., New York, 1959). However, reactions of isocyanuric acid with organic bases, i.e., amines, are hardly known.
While we were carrying out research on reactions of isocyanuric acid with various amines, we previously found that isocyanuric acid does not always form stable adducts by reaction with amines irrespective of the kinds of the amines and in other words, isocyanuric acid has such a selectivity to amines that it forms stable adducts with specific amines alone.